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Julien 75f94903b3
Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825)
* Add OpenAPI 3.2 specification generation for Prometheus HTTP API

This commit introduces an OpenAPI specification for the Prometheus API.
After testing multiple code-generation servers with built-in APIs, this
implementation uses an independent spec file outside of the critical path.
This spec file is tested with a framework present in this pull request.

The specification helps clients know which parameters they can use and is
served at /api/v1/openapi.yaml. The spec file will evolve with the
Prometheus API and has the same version number.

Downstream projects can tune the APIs presented in the spec file with
configuration options using the IncludePaths setting for path filtering.

In the future, there is room to generate a server from this spec file
(e.g. with interfaces), but this is out of scope for this pull request.

Architecture:
- Core OpenAPI infrastructure (openapi.go): Dynamic spec building,
  caching, and thread-safe spec generation
- Schema definitions (openapi_schemas.go): Complete type definitions
  for all API request and response types
- Path specifications (openapi_paths.go): Endpoint definitions with
  parameters, request bodies, and response schemas
- Examples (openapi_examples.go): Realistic request/response examples
- Helper functions (openapi_helpers.go): Reusable builders for common
  OpenAPI structures

Testing:
- Comprehensive test suite with golden file validation
- Test helpers package for API testing infrastructure
- OpenAPI compliance validation utilities

The golden file captures the complete specification for snapshot testing.
Update with: go test -run TestOpenAPIGolden -update-openapi-spec

REVIEWERS: The most important thing to check would be the OpenAPI golden
file (web/api/v1/testdata/openapi_golden.yaml). Test scenarios are important
as they test the actual OpenAPI spec validity.

Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>

* Add OpenAPI 3.1 support with version selection

Add support for both OpenAPI 3.1 and 3.2 specifications with version
selection via openapi_version query parameter. Defaults to 3.1 for
broader compatibility

Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>

* Enhance OpenAPI examples and add helper functions

- Add timestampExamples helper for consistent time formatting
- Add exampleMap helper to simplify example creation
- Improve example summaries with query details
- Add matrix result example for range vector queries

Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>

* web/api: Add AtST method to test helper iterators

Implement the AtST() method required by chunkenc.Iterator interface
for FakeSeriesIterator and FakeHistogramSeriesIterator test helpers.
The method returns 0 as these test helpers don't use start timestamps

Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>

* OpenAPI: Add minimum coverage test

Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>

* OpenAPI: Improve examples handling

Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>

---------

Signed-off-by: Julien Pivotto <291750+roidelapluie@users.noreply.github.com>
2026-01-29 13:36:13 +01:00
.github PR template: add a concrete release notes example (#17721) 2026-01-27 12:49:50 +01:00
cmd st: Add a hidden 'st-storage' feature flag for PROM-60 (#17907) 2026-01-28 09:05:54 +00:00
config Add test case for loading stale_series_compaction_threshold config 2026-01-24 16:32:44 -08:00
discovery Update Go yaml v3 library (#17913) 2026-01-22 16:36:30 +01:00
docs Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
documentation Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
internal/tools Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
model Update Go yaml v3 library (#17913) 2026-01-22 16:36:30 +01:00
notifier notifier: fix flaky TestStop_DrainingEnabled and TestStop_DrainingDisabled race conditions (#17938) 2026-01-29 08:07:32 +01:00
plugins Make service discoveries removable through build tags (#17736) 2026-01-08 10:06:33 -03:00
prompb fix(remote_read): NHCB not returned over remote read samples (#17794) 2026-01-07 08:44:57 +01:00
promql fix(promql): prevent panic in trimStringByBytes on invalid UTF-8 2026-01-24 16:06:42 +01:00
rules tests(teststorage): Close Storage in the helper (#17902) 2026-01-23 08:41:35 +00:00
schema Remove copyright date from headers (#17785) 2026-01-05 13:46:21 +01:00
scrape scrape: fix flaky appender test (#17962) 2026-01-29 10:50:17 +00:00
scripts scripts: use git ls-files and check go.work files in version check 2026-01-09 17:52:38 +01:00
storage otlptranslator: fix silently swallowed error in addSumNumberDataPoints (#17954) 2026-01-28 13:58:50 +01:00
template Remove copyright date from headers (#17785) 2026-01-05 13:46:21 +01:00
tracing Remove copyright date from headers (#17785) 2026-01-05 13:46:21 +01:00
tsdb tsdb: fix division by zero in stale series compaction (#17952) 2026-01-29 08:06:00 +01:00
util tests(teststorage, api_test): Fix leaking readers; kill fake exemplar storage (#17906) 2026-01-27 10:07:56 +00:00
web Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
.dockerignore Add image build for ppc64le architecture 2020-04-06 18:03:58 -03:00
.gitattributes Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
.gitignore Add Go workspace for multi-module development. 2025-12-19 12:43:15 +01:00
.gitpod.Dockerfile .gitpod.Dockerfile: Auto-fetch Go and goyacc vers 2024-05-24 09:17:18 +03:00
.gitpod.yml fix gitpod by using custome dockerfile and accurate npm ui path 2021-09-27 18:59:41 +02:00
.golangci.yml Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
.promu.yml bump go version across all stages 2025-09-02 10:02:39 +02:00
.yamllint Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
CHANGELOG.md fix typo in release notes about scrape_native_histograms (#17655) 2026-01-13 11:41:57 +01:00
CODE_OF_CONDUCT.md Update link for referenced CNCF code of conduct (#10664) 2022-05-03 18:32:23 +02:00
CODEOWNERS chore(codeowners): promote matt-gp external github user to owner of AWS SD (#17946) 2026-01-28 08:20:06 +01:00
CONTRIBUTING.md docs: Fix inaccuracies in root markdown files (#17433) 2025-12-27 13:50:19 +01:00
Dockerfile Add distroless Docker image variant 2026-01-19 14:39:59 +01:00
Dockerfile.distroless Fix ARG scoping in Dockerfile.distroless 2026-01-20 12:21:01 +01:00
go.mod Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
go.sum Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
go.work Add OpenAPI 3.2 specification generation for Prometheus HTTP API (#17825) 2026-01-29 13:36:13 +01:00
LICENSE Clean up license issues. 2015-01-21 20:07:45 +01:00
MAINTAINERS.md chore(maintainers): remove Nico from remote write maintainers (#17945) 2026-01-27 14:33:57 +00:00
Makefile Fuzzing: Move to go fuzzing 2026-01-12 12:59:10 +01:00
Makefile.common Merge pull request #17892 from roidelapluie/roidelapluie/pushver 2026-01-22 11:50:57 +01:00
NOTICE UI: Speed up alerts/rules/... pages by not rendering collapsed content 2025-11-06 11:32:59 +01:00
README.md Make service discoveries removable through build tags (#17736) 2026-01-08 10:06:33 -03:00
RELEASE.md Volunteer to shepherd the release v3.10 (#17822) 2026-01-09 15:00:53 +00:00
renovate.json fix: renovate configuration (#17793) 2026-01-06 13:34:29 +00:00
SECURITY-INSIGHTS.yml chore: provide OSSF security insight 2024-07-31 06:36:02 +00:00
SECURITY.md fix markdown lint issues (#10591) 2022-05-03 10:59:09 +02:00
ui-commits promql: rename holt_winters to double_exponential_smoothing 2024-09-19 15:29:01 +02:00
VERSION Cut v3.9.1 (#17804) 2026-01-07 16:05:27 +00:00

Prometheus
Prometheus

Visit prometheus.io for the full documentation, examples and guides.

CI Docker Repository on Quay Docker Pulls Go Report Card CII Best Practices OpenSSF Scorecard CLOMonitor Gitpod ready-to-code Fuzzing Status

Prometheus, a Cloud Native Computing Foundation project, is a systems and service monitoring system. It collects metrics from configured targets at given intervals, evaluates rule expressions, displays the results, and can trigger alerts when specified conditions are observed.

The features that distinguish Prometheus from other metrics and monitoring systems are:

  • A multi-dimensional data model (time series defined by metric name and set of key/value dimensions)
  • PromQL, a powerful and flexible query language to leverage this dimensionality
  • No dependency on distributed storage; single server nodes are autonomous
  • An HTTP pull model for time series collection
  • Pushing time series is supported via an intermediary gateway for batch jobs
  • Targets are discovered via service discovery or static configuration
  • Multiple modes of graphing and dashboarding support
  • Support for hierarchical and horizontal federation

Architecture overview

Architecture overview

Install

There are various ways of installing Prometheus.

Precompiled binaries

Precompiled binaries for released versions are available in the download section on prometheus.io. Using the latest production release binary is the recommended way of installing Prometheus. See the Installing chapter in the documentation for all the details.

Docker images

Docker images are available on Quay.io or Docker Hub.

You can launch a Prometheus container for trying it out with

docker run --name prometheus -d -p 127.0.0.1:9090:9090 prom/prometheus

Prometheus will now be reachable at http://localhost:9090/.

Building from source

To build Prometheus from source code, You need:

  • Go: Version specified in go.mod or greater.
  • NodeJS: Version specified in .nvmrc or greater.
  • npm: Version 10 or greater (check with npm --version and here).

Start by cloning the repository:

git clone https://github.com/prometheus/prometheus.git
cd prometheus

You can use the go tool to build and install the prometheus and promtool binaries into your GOPATH:

go install github.com/prometheus/prometheus/cmd/...
prometheus --config.file=your_config.yml

However, when using go install to build Prometheus, Prometheus will expect to be able to read its web assets from local filesystem directories under web/ui/static. In order for these assets to be found, you will have to run Prometheus from the root of the cloned repository. Note also that this directory does not include the React UI unless it has been built explicitly using make assets or make build.

An example of the above configuration file can be found here.

You can also build using make build, which will compile in the web assets so that Prometheus can be run from anywhere:

make build
./prometheus --config.file=your_config.yml

The Makefile provides several targets:

  • build: build the prometheus and promtool binaries (includes building and compiling in web assets)
  • test: run the tests
  • test-short: run the short tests
  • format: format the source code
  • vet: check the source code for common errors
  • assets: build the React UI

Service discovery plugins

Prometheus is bundled with many service discovery plugins. You can customize which service discoveries are included in your build using Go build tags.

To exclude service discoveries when building with make build, add the desired tags to the .promu.yml file under build.tags.all:

build:
    tags:
        all:
            - netgo
            - builtinassets
            - remove_all_sd           # Exclude all optional SDs
            - enable_kubernetes_sd    # Re-enable only kubernetes

Then run make build as usual. Alternatively, when using go build directly:

go build -tags "remove_all_sd,enable_kubernetes_sd" ./cmd/prometheus

Available build tags:

  • remove_all_sd - Exclude all optional service discoveries (keeps file_sd, static_sd, and http_sd)
  • enable_<name>_sd - Re-enable a specific SD when using remove_all_sd

If you add out-of-tree plugins, which we do not endorse at the moment, additional steps might be needed to adjust the go.mod and go.sum files. As always, be extra careful when loading third party code.

Building the Docker image

You can build a docker image locally with the following commands:

make promu
promu crossbuild -p linux/amd64
make npm_licenses
make common-docker-amd64

The make docker target is intended only for use in our CI system and will not produce a fully working image when run locally.

Using Prometheus as a Go Library

Remote Write

We are publishing our Remote Write protobuf independently at buf.build.

You can use that as a library:

go get buf.build/gen/go/prometheus/prometheus/protocolbuffers/go@latest

This is experimental.

Prometheus code base

In order to comply with go mod rules, Prometheus release number do not exactly match Go module releases.

For the Prometheus v3.y.z releases, we are publishing equivalent v0.3y.z tags. The y in v0.3y.z is always padded to two digits, with a leading zero if needed.

Therefore, a user that would want to use Prometheus v3.0.0 as a library could do:

go get github.com/prometheus/prometheus@v0.300.0

For the Prometheus v2.y.z releases, we published the equivalent v0.y.z tags.

Therefore, a user that would want to use Prometheus v2.35.0 as a library could do:

go get github.com/prometheus/prometheus@v0.35.0

This solution makes it clear that we might break our internal Go APIs between minor user-facing releases, as breaking changes are allowed in major version zero.

React UI Development

For more information on building, running, and developing on the React-based UI, see the React app's README.md.

More information

  • Godoc documentation is available via pkg.go.dev. Due to peculiarities of Go Modules, v3.y.z will be displayed as v0.3y.z (the y in v0.3y.z is always padded to two digits, with a leading zero if needed), while v2.y.z will be displayed as v0.y.z.
  • See the Community page for how to reach the Prometheus developers and users on various communication channels.

Contributing

Refer to CONTRIBUTING.md

License

Apache License 2.0, see LICENSE.